It has been nearly two decades in the making, but as NASA will tell you, hard work absolutely pays off. Especially when that payoff comes in the form of the Electromagnetic Drive (or EM Drive), which appears to defy physics, or at least physics as we understand it today.
Last week, NASA’s peer-reviewed EM Drive paper was published under the title, “Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum” as an open-access “article in advance” in the American Institute of Aeronautics and Astronautics (AIAA)’s Journal of Propulsion and Power. It’s a monumental achievement for NASA, which has been grappling with the concept of the propulsion system since it was first proposed back in 1999 by British inventor Roger Shawyer.
In theory, the EM Drive doesn’t use rocket fuel, but rather sends microwaves back and forth within a conical metal cavity in order to produce thrust. As per Shawyer’s original estimates, the unprecedented efficiency of the EM Drive could send a rocket to Mars in only 10 weeks. Sound too good to be true? According to physics as it is understood today, it is. That’s because the EM Drive doesn’t adhere to Newton’s third law, which dictates that all action has an equal and opposite reaction. The EM Drive, however, seems to produce thrust without pushing anything else back.
The folks at NASA decided to put an actual EM Drive to the test, and the results of their experimentation comprise the contents of the newly published paper.
It is cool that the experiment showed the drive works. That does not automatically guarantee that it works better than current propulsion systems. They noted that the amount of thrust they were getting was tiny, but also that they haven’t yet fine-tuned the thruster for maximum thrust.
Currently, the best numbers I’ve seen reported for this device are by the Chinese group from 2008, who reported a thrust of 750 millinewtons when they powered the thruster with 2.5 kilowatts of electricity. The “milli” in millinewtons means this amount of thrust was really very small. It would take 4,450 milliewtons of thrust to hit something with a pound of force. So this thing can generate about a sixth of a pound of thrust as of now, and to do that you have to charge it with 2.5 kilowatts of electricity.
2.5 kilowatts is pretty large. It’s about what the water heater in your house burns each hour to keep your hot water hot (I think), assuming your water heater runs on electricity. So the best results on this thing so far are really dismal right now. If my calculations are right, the amount of electricity you have to use to give this thruster a pound of thrust is equivalent to the amount of electricity used by six houses every hour to keep their hot water hot. That’s not efficient at all compared to current propulsion methods. Here’s hoping our scientists can optimize it. In its current form, I don’t think it will be replacing your car engine, not unless you want to carry a battery the size of a house and creep along at a rate of a pound of thrust per hour.
Well keep in mind when it comes to crazy new tech like this, its likely the data they allow the public to have access to, is just a small fraction compared to what they truly have, but keep it locked up in secret access projects, black budget DARPA stuff.
Another good example was how the Govt explained away many UFO sightings back in the 50s,60s, 70s as being secret experimental testing of aircraft and propulsion systems, well we know for a fact this was true, and eventually we got the stealth bomber, TR3B, etc, so paying attention to what UFO reports look like today…its usually totally silent aircraft that can hover, stop on a dime, accelerate instantly, some degree of cloaking technology, that is a pretty good indicator what they are really working on and what they really have in these SAPs.
Well, leaving orbit and travel between planets are different beasts. We may still require the short-term thrust of rocket power to break a planet’s gravitational pull even if this drive is perfected, but in terms of long-term propulsion across the vacuum it may be more efficient, require less weight, allow the achievement of greater speeds, and longer journeys…
Rocket technology is used to punch us in the right direction but then lets Newton’s first law take over as itis not run continuously and does not provide constant acceleration. This could be run continuously.
Astronomy Magazine says, “the device puts out 1.2 millinewtons of thrust — or enough to accelerate a satellite weighing one kilogram to one mile per hour over the course of about six minutes. … Other fuel-free methods of propulsion…such as light sails and laser propulsion…are orders of magnitude weaker than the EmDrive claims to be.”
Ars Technica says, “In one experiment at 60 Watts of microwave power, the authors measure thrust of 128 microNewtons.”
128 microNewtons is about the same as 1.2 milliNewtons. The American experiment gives us 1.2 milliNewtons when the device is powered by 60 watts. The Chinese guys got 750 millinewtons when they powered the thruster with 2500 watts. That’s equivalent to 75 mN at 250w, or 3 mN at 10w.
3 mN at 10w is much better than what we Americans got. We got 1.2 mN at 60w. The Chinese one gets over twice the thrust for a sixth of the electricity. The Chinese result is the best result I’ve seen so far, and it is still extremely low compared to fossil fuel power. If my calculations are right, the power usage is equivalent to generating a pound of thrust every six minutes for the same amount of electricity it takes to power six houses’s water heaters for an hour.
That’s incredibly inefficient compared to fossil fuels, but it gets more reasonable when you consider the use case: they want to use it for traveling within the solar system, where you can power the thing with solar panels. In space, it’s more reasonable to run a ship on just a pound of thrust every six minutes, because there’s no friction to make the thrust wear off. It just keeps on adding up, an additional pound of thrust every six minutes, until the speed is ridiculously high. It’s clever for space, and as the article says it’s an order of magnitude better than our other options. But for land-based travel, with our friction impeding things, it’s useless as far as I can see.